The present invention relates generally to a capacitive humidity sensor with hysteresis compensation.
A humidity sensor is a device used for measuring the moisture content in an environment. Humidity sensors typically rely on the measurement of some other property than humidity such as a change in mass, a change in electrical capacitance, and/or a change in electrical resistance of a substance as moisture is absorbed or discharged. In particular, with respect to capacitive based humidity sensors, the humidity has an effect on a dielectric constant of a polymer substance, metal oxide substance, or otherwise. The change in the dielectric constant is measured to determine the humidity. Unfortunately, the accuracy of humidity sensors is limited due to many factors, including for example, temperature, contamination, drift, hysteresis, and/or aging effects.
What is desired therefore is a capacitive humidity sensor with compensation to improve its accuracy.
The foregoing and other objectives, features, and advantages of the invention may be more readily understood upon consideration of the following detailed description of the invention, taken in conjunction with the accompanying drawings.